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pH dependent absorption and fluorescence spectra of hypericin 1 and its octahydroxy analogue 3 demonstrate their acidic properties, their deprotonation occuring in the ground and excited states from OH in the bay region and in the peri position to the carbonyl, respectively; the presence of the anion of 1 in the crystalline state is established by X-ray diffraction.

Samples of (R)- and (S)-[2-2H]cadaverines 10 and 12 prepared from L and D-glutamic acid, respectively, were fed to Lupinus luteus plants and the labelling patterns in lupinine 1 determined by 2H NMR spectroscopy demonstrated that the quinolizidine ring system is formed by removal of the pro-S hydrogen and retention of the pro-R hydrogen at C-1 of lupinine.

AM1 and PM3 SCF-MO calculations suggest the dimerisation of hemifullerene 1 to 2 by a mechanism involving six concurrent π2s+π4s additions corresponds to a stationary point with six negative force constants; the first stepwise π2s+π4s transition state is found to be highly unsymmetrical with a large barrier to reaction.

Ab initio calculations predict planar transition states for bowl-to-bowl inversions in corannulene, ethenocorannulene and semibuckminsterfullerene with barriers of 14.4, 34.4 and ca. 74 kcal mol–1, (1 cal = 4.184 J), respectively, but a non-planar transition states for 1,2-dihydrocorannulene with a barrier of 10.9 kcal mol–1.

Syntheses of 4,7-diamino-2,9-dimethyl-5,6,11a-triaza-6,11,11a,12-tetrahydronaphthacene and of their 2-naphthoyl and butyroyl amide derivatives are described; the U-shaped 2-naphthoyl derivative stabilizes as an interlocked dimer in CDCl3 solution.

The first synthesis of the parent TMM-C60 adduct 1 was achieved by means of Pd°-mediated [3 + 2] cycloaddition and its structure was unambiguously proved by spectroscopic means (1H and 13C NMR and MS); a pentane solution of the adduct 1 exhibited a fluorescence emission spectrum with λmax 704 nm and vibronic fine structure at ambient temperature.

The role of 7-oxanorbornenomaleimide 9 as an intermediate in cavity molecule construction is evaluated and other cycloaddition reactions are used to complete the sequence to 1 or 2.

A method is described for constructing totally rigid triad(trichromophoric) supramolecular systems, D2–B1–D1–B2–A, in which the chromophores D2(dimethylaniline), D1(dimethoxynaphthalene), and A(dicyanovinyl) are fused to bridges, B1 and B2, consisting of linearly fused norbornyl and bicycle[2.2.0]hexanyl units.

A series of macrocyclic tris(indolylmethylene) compounds (calix[3]indoles] can be obtained from 7- or 2-hydroxymethylindoles or from the combination of either an indole with a bis(hydroxymethyl)-2,7′-diindolylmethane or a bis(hydroxymethyl)indole with a 2,7′-diindolylmethane; an isomeric series can be obtained from the combination of an indole with a bis(hydroxymethyl)-2,2′-diindolylmethane.

Dipotassium tribenzodihydroacepentalenediide 42– reacts with electrophiles to give 4,7-disubstituted tribenzodihydroacepentalene derivatives 3 with a highly pyramidalised double bond, as evidenced by X-ray structural determinations; protonation of the dianion 42– yields an interesting polycyclic [2 + 2] dimer 5.

The synthesis and characterization of a new planar bisphthalocyanine derivative substituted with 12-ethylhexyloxy side chains 2b is described; a similar compound was reported previously, but it is shown here that it probably corresponds to a protonated form of the actual derivative.

A cleanly separated Diels–Alder product of C60, a 1 : 1 adduct of anthracene, has been synthesized and characterized by thermogravimetric analysis, and NMR, UV–VIS, IR and mass spectroscopies.

Macrocycle 2, which is obtained in 86% yield from calixarene analogue 1 by Birch reduction, does not undergo intramolecular benzene-ring rotation between room temp, and 125 °C according to variable temperature (VT) NMR experiments and derivative 3 is an ionophore for alkali metals, transition metals and lanthanoids.

A new type of strongly binding and chiral spherand is reported, which js composed of a phenanthroline and four alkoxy benzene units incorporated in 18-membered rings whose binding free energies and 1H NMR spectra suggest the systems to be preorganized for complexation.

The cycloadduct 2 derived from reaction of 3-methoxyestra-1,3,5(10), 14, 16-pentaen-17-yl acetate 1 with 2-chloroacrylonitrile undergoes a tandem reaction sequence in the presence of alkali, leading to (161R)-3-methoxy-17-oxo-15β, 161-cyclo-14, 16β-ethano-14β-estra-1,3,5(10)-triene-161-carbonitrile 4, the X-ray crystal structure of which is reported; compound 4 is converted into new ring D bridged analogues of estrone.

Crystals of 1,4,8,11,15,18,22,25-octa-iso-pentyloxyphthalocyanine are comprised of tilted stacks of molecules, the individual molecules being well separated by the alkoxy chains.

Vacuum pyrolysis of the dialkylphosphate esters of p-tert-butylcalix[4]arene and p-tert-butylcalix[6]arene results in phosphorus polybridged systems which display dynamic processes.

Ab initio calculations show that electropositive substituents such as silyl groups have a remarkable effect on the relief of strain from polycyclic silicon compounds, the same effects being predicted also for the still heavier polycycles.

15,16-Dihydro-11-trifluoromethylcyclopenta[a]phenanthren-17-one 7, an electronegative analogue of the strongly carcinogenic 11-methyl-17-ketone, is synthesised in three steps from 17,17-ethylenedioxy-11,12,13,14,15,16-hexahydrocyclopenta[a]phenanthren-11-one 3.

Crystals of 1,4,8,11,15,18,22,25-octahexylphthalocyanine are composed of tilted stacks of molecules with an unexpectedly large separation between the aromatic cores.

An electrochemical procedure is used to reduce 2,3-dicyanonaphthalene into the lithium naphthalocyanine radical (NPcLi·): a new material with semiconducting properties.

By comparison of the 19F chemical shift of p-fluorophenyl substituted Coates cation 1 with that of triasteryl cation 2, πσ-participation by the remote cyclopropyl group in ion 1 is shown to be more effective than σ-participation by the adjacent cyclopropyl group in ion 2 in the delocalization of positive charge.

Electrophillic bromination occurs regiospecifically at the antipodal pyrrolenic ring of free-base porphyrins bearing substituents that fix the aromatic delocalization pathway; this new feature of porphyrin chemistry is not observed in the reactions of the corresponding metalloporphyrins as the pre-requisite bond fixation is only possible in free-base compounds.

An approach to molecular wires based on quasi-one-dimensional linearly conjugated poly-porphyrin systems is outlined and a rationally designed synthesis of the tetrakisporphyrin 9, a strand some 65 A in length, via the bis(porphyrin)tetraone 2 is described.

The staurosporine aglycone 3 has been synthesised in 22.6% overall yield from ethyl indole-2-acetate by a route which involves an intramolecular Diels–Alder reaction of the pyranoindolone 8 followed by nitrene mediated cyclisation.

Orange acenaphthylene-1,2-dicarboxylic anhydride undergoes a solid state photochemical [2 + 2] cycloaddition upon irradiation at 390 nm to yield a white photodimer which can be cleaved back to two monomers by irradiation at 300 nm; this process can be repeated numerous times.

Thermal isomerization of allenyl ether (1b) proceeds by intramolecular [2 + 2] cycloaddition to give (4), whereas the higher homologue (1c) is transformed by an alternate mode of [2 + 2] cycloaddition to the unstable alkene(7), which spontaneously dimerizes to (8) and (9); X-ray determinations confirm the structures of (8), (9), and lactone (6) derived from (4).

An o-iodinated phenolic tetrahydrofurobenzofuran intermediate has been prepared with the correct regiochemistry and converted into aflatoxin B2.

Proximal 1,2-bis-demethylation of tetramethoxy-p-t-butylcalix[4]arene 1 has been achieved for the first time by Ti(IV)-assisted reaction, which allows the synthesis of a new type of calixarene-based bis-crown ether.

Later oxidation processes in biosynthesis of betaenone B (2) were examined by a simple method involving preparation of isotopically labelled probetaenone I (1) from [1-14C]- and [1,2-13C]-acetate and [S-13CH3]methionine in Phoma betae and their efficient conversion to (2); the results show that (1) is an intermediate for formation of (2).

It has been demonstrated that in poriferasterol, biosynthesized in Ochromonas malhamensis, the hydrogen atom originally present at C-24 of the Δ24-precursor is located at C-25.

New routes to quinone-type i.r. dyes for optical recording media have been developed by the ring-closure reaction of halogenoquinones with potassium 2-aminobenzenethiolate or zinc 2-aminobenzeneselenate.

The synthesis of molecular 3.06, 5.28, and 7.50 nm lines, composed of polyacenequinone units, via repetitive Diels–Alder reactions is reported.

A cyclic trinuclear porphyrin host has been synthesised; its binding properties show that it has a spacious cavity which prefers an open conformation but which can close around small bidentate ligands such as 4,4′-bipyridyl.

The first chemical correlation of a lycoctonine with an aconitine alkaloid has been achieved by selective removal of the hydroxy group at C-7 in lycoctonine (1) utilizing Huang-Minlon reduction of hydroxylycoctonine (3); the crystal structure of the aconotine alkaloid (2) has been determined.

The cisoid, transoid, transoid- and all cisoid-trimers of benzocyclobutene were synthesised from 1,2-dibromo-1,2-dihydrobenzocyclobutene using nickel-catalysed cyclo-trimerisation; thermal ring-opening of the all-cisoid-trimer gave Z,Z,Z-tribenzo[a,e,i]cyclododedcene (Z,Z,Z-tribenz[12]annulene) which can be converted into its silver and chromium complexes.

The hydrolysis of diazotized 5-amino-[3.3]paracyclophane and anti-4-amino[2.2](1,4)naphthalenoparacyclophane gives products having a barrelene structure, presumably via an aryne mechanism.

13-Methylberberine (6a), dehydrocorydaline (6b), and corysamine (6c, and their tetrahydro derivatives (9a–c) were efficiently synthesised from the corresponding protoberberines (1) through photochemical electrocyclic reaction of 13-methylene-8, 14-cycloberbines (3).

The structure determination and synthesis of sterllidimine (1), the first ellipticine-derived bisindole alkaloid isolated from Strychnos dinklagei(Loganiaceae), are reported.

The title compound (1b), a new non-planar chlorocarbon possessing approximate D3d symmetry, has been prepared by chlorination of coronene (1a); complete substitution of (1b) by arenethiolate nucleophiles in the dipolar aprotic solvent DMEU (1,3-dimethylimidazolidin-2-one) yields the dodecathioethers (2a) and (2b), members of a new prospective host series.

Multiple (amine + aldehyde) condensation gives the macrobicyclic cryptands (1) and (3) in high yield; (1) gave a dinuclear CuI cryptate and was reduced to a polyamine (2) which binds anions, when protonated.

Cyclic flavins with planar chirality (chiral flavinophanes) can oxidise thiols (ca. 43% enantiomeric excess) and NADH model compounds (ca. 60% enantiomeric excess) in an asymmetric manner.

Chemical evidence, supported by an X-ray crystal structure determination, shows that a furan adduct of hexachloronorbornadiene unambiguously belongs to the endo–exo series of cycloadducts (typified by aldrin), and not the endo–endo series of isomers.

4,6-Dimethoxy-3-methylindole can be converted by treatment with aryl aldehydes and phosphoryl chloride in chloroform into macrocyclic tri-indolyl methanes, with the indole rings linked at C-2 and C-7.

Natural granaticin (1) has been synthesized by joining the chiral left and right fragments, (5) and (10), and subsequent lactonization of the resulting product (11) and oxidative O-demethylation.

The Structure of a new bis-cyclotribenzyl cavitand, (2), forming an internal 1 : 1 Complex (‘cavitate’) with dichloromethane, has been determined by single X-ray crystallography.

Dihalides X–(Z)–X, [Z =(CH2)n; n= 1–7 or CH2CHCHCH2] react with the phenol group of vanillyl alcohol to give the dialkylated derivatives HOCH2–Ar–O–(Z)–O–Ar–CH2OH (2), which in turn, in the presence of formic acid, afford the corresponding D3 cryptophanes (3), with, in some cases, minor amounts of the C3h isomers (4).

The first crystal structures of a catenane and of a metalio-catenate are reported; upon complexation with CuI, there is a dramatic change in molecular shape.

A novel optically active double-layered bis-crown ether (–)-(S,S)-(7) with a diphenanthrylnaphthalene moiety as the chiral centre has been prepared, and examination of its chiral recognition behaviour showed that (–)-(S,S)-(7) has a high enantiomer selectivity for 1,6-diphenylhexamethylene-1,6-diamine.

Intramolecular cyclization of porphyrins substituted with either propanoic or butanoic acid side chains led to the formation of the cyclic ketones (3c) and (4d) from which the petroporphyrins (3b) and (4c) were obtained; treatment of (4c) under acidic conditions did not result in rearrangement of the seven membered exocyclic ring.